The invention provides a low-scattering shell for assembling a binary nozzle engine. The low-scattering shell is of a flat droplet-shaped structure and comprises a front section and a rear section, the front section comprises a concave opening part, the rear section comprises a cone part and a protruding part matched with the concave opening part, the front edge of the protruding part and a part,matched with the front edge, of the concave opening part each comprise a sawtooth structure, and when the binary nozzle engine is arranged in the concave opening part to carry out an electromagnetic test, a nozzle of the binary nozzle engine is exposed by the concave opening part, and the size, in the width direction, of the concave opening part is matched with the nozzle.